Aerobic granulation

Le Ngoc Thuan** 김 투안 **

Aerobic granulation as a novel environmental biotechnology is tailored for treating a wide variety of wastewaters

Similar to anaerobic granulation, aerobic granulation is believed to be a microbial self-immobilization process that is driven by selection pressures in SBR

Anaerobic granulation technology had been well developed for high strength organic wastewater treatment in the past two decades.

However, anaerobic granulation technology has drawbacks• long start-up period, • high operation temperature and • no application for low-strength organic wastewater.

The biological treatment of wastewater in the waste water treatment plant often accomplished by means of the application of conventional activated sludge systems.

These systems generally require large surface areas for implantation of the treatment and biomass separation units due to the usually poor settling properties of the sludge.

Previous research showed that aerobic granules had

• compact and strong microbial structure, excellent settleability,

• high biomass retention and• ability to handle high strength wastewater.• The cost can be reduced by at least 20%

and space requirements can be reduced by as much as 75% (de Kreuk et al., 2004[6]).

It has been believed that aerobic granulation is independent on the characteristics of substrate, e.g. aerobic granules can grow on acetate, ethanol, glucose, phenol and synthetic wastewater

Composition of synthetic wastewater (SWW)

(Yarlagadda et. al., Formation of aerobic granules in the presence of a synthetic chelating agent. Environmental pollution 153 (2008) 37-43) modified

Chemical Concentration (mM)

CH3COONa 2560mg/L

MgSO4.7H2O 25mg/L

CaCl2.2H2O 30mg/L

NH4Cl 200 mg/L

K2HPO4 45 mg/L

Seed sludge 500ml of wastewater containing activated sludge flocs

Nutrient sol’n 1ml

Using tap water for reactor

Nutrient solutionFeCl3 900.44mg / FeCl3.6H2O (MW 207.3) 1499.62mg

H3BO3 150mgCuSO4’5H2O 30mgKI 180mgMnCl2’ 4H2O 60mgZnSO4’7H20 120mgCoCl2’7H2O 150mg / CoCl2’6H2O (MW 237.93) 139.45mg

MoO3 36mg

To 1000ml with D.W

(3)

J.-H. Tay, Q.-S. Liu and Y. Liu Microscopic observation of aerobic granulation in sequential aerobic sludge blanket reactor. Journal of applied Microbiology 2001, 91, 168-175

(1) Feeding tank, synthetic wastewater

(2) Feeding pump

(3) Programming time controller

(4) Oxygen supply aerator

(5) Air flow meter

(6) Air diffuser

(7) Aerobic reactor

(8) Over loading control

(9) Effluent / sampling port

(10) Sludge discharge

(1)

(2)

(3)

5cm

1.2m

(4) (5)(6)

(7)

(8)

(9)

(10)

Effect of settling time

R1: 20minR2: 15minR3: 10minR4: 5min

Filamentous bacteria and granular formation

Substrate concentration and filamentous bacteria

Filamentous microorganisms are slow-growing

they have very low maximum specific growth rate (Amax).

Strong evidence suggests that DO deficiency favors filamentous growth

DO concentration is maintained between 2.0 and 5.0 mg/L

Researches in

Environmental Engineering Lab

From lab-scale to large-scale…

Constructed wetlands

Thank you for your attention!